Abstract:The contents of soil organic carbon (SOC),dissolved organic carbon (DOC),and microbial biomass carbon (MBC),as well as profile distribution and its relationships in the four main soil types (Lime concretion black soils (LS),Fluve-aquic soils (FS),Paddy soils (PS),and Red soils (RS)) in Anhui Province are studied. Results showed that the contents of SOC,DOC,and MBC were significantly different in the four soils,but the trend of their profile distributions was basically the same. The contents in topsoil were higher and decreased with soil depth increasing. The orders of SOC,DOC,and MBC in topsoil were PSLSFSRS,LSFSPSRS,and FSLSRSPS,respectively. DOC and MBC were only a small part of SOC. The percentages of DOC and MBC over SOC were in the range from 4.92% to 18.97% and from 1.86% to 5.68%,respectively. There was a close relation among SOC,DOC,and MBC. The relationships between SOC and DOC,between SOC and DOC,and between DOC and MBC were all significant or very significant at 10%,5% or 1% level,respectively.